This invention relates to a medical instrument comprising mutually bonded tubular members of flexible resin.
In general, most medical instruments include a plurality of parts of soft or flexible material which are bonded to one another. One such example is a winged venous infusion needle assembly. A needle is secured in a hub or connector of flexible polyvinyl chloride resin which is, in turn, bonded or connected to a tube of flexible polyvinyl chloride resin with an adhesive of the solvent type using, for example, tetrahydrofuran (THF) and methyl ethyl ketone (MEK). The use of solvent-type adhesive, however, gives rise to a number of problems. (1) Solvent attacks parts to be bonded which become brittle or weak and will eventually be broken. (2) Some material is dissolved from parts by solvent and will undesirably block a flowpath. (3) Residual solvent leaves the risk of toxicity. Medical instruments having parts bonded with such solvent-type adhesive suffer from these and other problems. There is the need for a technique capable of bonding parts without using an organic solvent.